The present invention relates to a novel apparatus and method for surgical wound closure applications. Numerous medical applications exist where sealing of biological tissue is desired. U.S. Pat. No. 5,510,102 to Conchrum identifies a variety of applications including traumas of the liver, spleen, pancreas, lung, bone, etc., cardiovascular and vascular applications, such as microvascular anastomoses, vascular grafts, intraoperative bleeding and aortic repair; and the like.
The described invention provides a means to remove the heparin from anticoagulated whole blood. A sample of blood intended for either diagnostic analysis or therapeutic use is drawn into a blood collection apparatus. The blood is exposed to a material that has an immobilized substrate that removes a negatively charged anticoagulating agent, preferably heparin, from the sample. Blood drawn into and across the immobilized biomaterial will be deheparinized, and therefore will be capable of clot formation.
The most prominent application is the sealing of a vascular wound resulting from percutaneous entry, as is frequently encountered in angiography, angioplasty and atherectomy procedures. Percutaneous vascular access is typically required in the context of minimally invasive surgical procedures. These techniques are often used to reduce trauma to the patient. Reduced trauma typically translates to improved patient comfort, minimized procedural complications, and lower costs. The vessel accessed is typically the femoral or radial artery. Access involves placement of an introducer's distal tip beneath the patient's skin and through the arterial wall. To the extent possible, percutaneous access preserves the integrity of the tissue covering the artery. As a result, when the introducer is to be removed, the arterial access site is not exposed and the arterial wound is preferably closed without cutting down through the overlaying tissue to expose the site.
To accomplish hemostasis at the wound, numerous methods of post-introducer arterial closure have been tried. The prior art devices used in these methods may be broadly classified into two groups, those that mechanically achieve hemostasis and those that rely on clotted blood or components of blood to form all or a part of the hemostatic agent. By example, sutures, whether placed through an open surgical exposure of the artery or by means of a device designed to place sutures percutaneously are associated with mechanical methods, as these methods rely on mechanically closing the opening in the artery. The second group, those using clotted blood, include the predominant method of treatment, manual compression of the wound site. In this method, after the effects of any anticoagulating drugs have worn off, an attendant applies compression to the wound site until a clot of sufficient strength has formed to stop the bleeding. Alternatively, the attendant may apply any of various mechanical devices that will hold compression, such as a sand bag or a pneumatic clamp, until hemostasis is achieved.
Recently, a variety of devices have entered the market that aid in achieving hemostasis, even in the event of a patient whose blood is still actively anticoagulated. These devices typically rely on mechanical methods such as sutures or upon various biologic substances, such as collagen and thrombin that are known to induce clotting of blood even when anticoagulating agents are present. The differences between the devices are largely in the delivery platforms used to position the biologic materials. Disadvantages of the prior art devices and methods vary depending on the method employed. Generally speaking, mechanical devices that deploy sutures are complex, expensive and technically difficult to employ. In addition, mechanical closure of the opening in an arterial wall can lead to a permanent restriction at that site as the diameter of the artery is reduced when the opening is pulled together, much like a purse string. Open vascular access closure by means of suturing requires the skill of a specialist, a vascular surgeon, a specialist not required for the procedure itself and, therefore, an additional expense. Suturing by means of a specially designed percutaneous device offers the advantage of a very rapid cessation of bleeding through the arteriotomy, but can lead to significant issues if the device malfunctions and becomes entangled in place. In addition, secondary bleeding, that from the capillary bed of the adjacent soft tissue can be left untreated. This secondary bleeding can continue for extended periods, causing weeping at the wound site and potentially leading to infections.
Current methods, which rely in whole or in part on clotted blood, also suffer from significant drawbacks. The compression method requires that the patient's blood return to normal clotting status by means of the natural metabolization of anticoagulating drugs. This process can take several hours, a period during which the patient must remain in the vicinity of the catheterization lab with the procedural sheath still in place. The compression period, once it begins, can last for extended periods, sometimes more than two hours. This process is uncomfortable for the patient, often painful, and is tedious for the attendant or attendants as well. In addition, hemorrhaging can occur if the site is not held properly or if the compression period is terminated too early. Also, due to the time involved, both in terms of attendant time and cath lab time, this process tends to be quite expensive.
The devices, which have been designed to be used in association with methods that improve on devices using clotted blood, generally work in a more rapid manner, but not without additional risks. The biologic materials employed, collagen and thrombin, are very potent clot inducing substances, so much so that if they are inadvertently deployed into the artery rather than outside adjacent to the artery, a limb or life threatening clot may form inside of the artery. This condition can be difficult to treat and, in the best of circumstances, require dramatic, extensive intervention. In addition, the biologic materials used are derived from animal sources, typically bovine, and therefore, bring along other inherent risks associated with such sources. Included among these risks are allergic reactions and the possibility of contracting bovine spongiform encepholapathy (BSE), otherwise known as “mad cow's disease.” The prior art devices are often technically difficult to use and their use can inhibit reaccess at the same site in situations where an additional procedure needs to be performed on the patient, such as in an emergency follow-up procedure. Transmission of infectious disease can also occur when the material used is manufactured from pooled human blood as reported in Opth. Surg., 3:640 (1992). Autologous preparations like fibrin glue, as described in U.S. Pat. No. 5,674,394 to Whitmore, are well known, but significant preparation with the associated labor and material costs is required and typically, an additional thrombin material is still required at the wound site.
Despite the need for a device and a method that overcomes the limitations of the prior art, the prior art devices and methods have failed to adequately address the needs for a rapid and efficacious method of closing vascular and other wounds. Accordingly, it will be appreciated that there is a need for an efficient way of closing wounds. The present invention provides advantages over the prior devices and the prior methods used to close wounds, and also offers other advantages over the prior art and solve other problems associated therewith.